This invention relates to an accessory for blow molding machines and particularly to one for transferring container labels from a storage magazine to an article forming mold cavity such that the labels become molded into the final product.
Blow molding machines are used to produce various articles such as containers for household chemicals and other substances. In typical blow molding processes, a pair of old halves are clamped together around a tubular molten parison of thermoplastic material which is inflated by gas pressure to conform to the old cavity. Frequently, labels for product identification, instructions, warnings, etc., must be applied to the containers. In the past, containers were sent to a separate work station where labels were adhesively bonded to the container. More recently, however, a class of blow molding machines has been developed having in-mold labeling capability. For these machines, labels are transferred from a storage magazine and deposited directly into the molds prior to forming the article. Vacuum ports within the molds maintain the labels in position as they are clamped around the molten parison of thermoplastic material. When the parison is inflated, the labels become thermally bonded to the container outer surface. This process of in-mold labeling provides a label which is quite durable, less likely to peel off the container, and is more aesthetically desirable since it is molded flush with the container surface.
Numerous methods are presently employed in carrying out in-mold labeling processes. In accordance with this invention, an in-mold labeling accessory for blow molding machines is provided featuring improvements in the manner in which labels are located, and in reliability of loading labels into the molds.